1. The Field of the Invention
The present invention relates to treadmills, and more particularly to treadmills with adjustable cushioning members to manually, adjustably cushion the impact when a user is operating the treadmill.
2. Present State of the Art
Treadmills have become increasingly popular in recent years as a piece of exercise equipment. Treadmills can be used for either running or walking indoors such as at home or in the office. Most exercise treadmills include an exercise platform that includes an elongated frame with a first and second roller assembly mounted across opposite lateral ends of the frame. An endless belt is mounted for travel about the roller assemblies. The belt is flexible and unable to rigidly support the weight of the user. The belt is usually supported by a deck that is disposed between the upper portion of the belt and the frame. The deck is usually made of rigid material. The belt is controlled by a motor. As the user walks or runs on the belt, the belt is pressed against the underlying deck to provide mechanical support for a user.
In some types of treadmills, the decks were directly affixed to the frame to provide rigid support. As a result, the shock from the user's step is reflected by the deck back to the foot, ankle and leg of the user in a similar manner as the reactive forces are imposed on a walker, a jogger or a runner exercising on a hard-paved surface or a sidewalk. Over long periods of time, the shock experienced by the user can have detrimental effects to the joint of the user. Even in the short term, exercising on a rigid surface may prove to be tiring and jarring to a user. Attempts have been made to provide a way to cushion the impact felt by the user on the treadmill while still providing a rigid support surface for the belt and exerciser.
One method of attempting to cushion the impact felt by the user is to provide an intricate shock absorbing system which was attached to both the frame and the deck. The intricate shock absorbing system, however, is difficult to manufacture and cost prohibitive. Another attempt to provide cushioning to the user has been attaching rubber blocks or cushioning strips mounted along the length of the frame prior to mounting the deck to the frame. One problem with the rubber blocks or cushioning strips mounted between the deck and frame is that the blocks did not deform equally between users having different weights. As a result, for some users there was insufficient cushioning and with another user the treadmill was too soft. Another method of providing cushioning on treadmills is the use of several elastomeric springs that are positioned between the frame and the deck. The elastomeric springs were intended to provide an amount of resistance that is proportional to the extent that the deck deflected in response to a user exercising.
As recognized with the use of rubber blocks, users that have differing weights do not obtain the same amount of deflection of the deck and therefore need differing amounts of cushioning. In addition, the amount of cushioning that is desired may depend upon the exercise that is being performed on the treadmill. For instance, a user who is running on the treadmill will most likely need more cushioning than a user who is walking on the treadmill. In addition, there is often just a difference of personal taste in the amount of cushioning that is desired. Some users may prefer to exercise on a firmer surface while others would prefer to exercise on a surface with a great deal of cushion. One attempt to provide a treadmill that could provide individualized cushioning required physically removing strips of cushioning material and inserting other strips into the treadmill. This was time consuming and awkward.
What is needed is a treadmill in which a user may manually adjust the amount of cushioning that will be provided without having to disassemble and remove pieces of the treadmill.